T-Mobile CEO John Legere is known for being outspoken on social media, from spats with a certain bloviating presidential candidate to digs at his rival carriers.

His latest jab at Sprint, however, appears to have touched a nerve with its CEO, Marcelo Claure. Legere criticized Sprint's new "All-In" plan as a "swing and a miss," and Claure responded by slamming T-Mobile's "Uncarrier bulls**t."

@JohnLegere I am so tired of your Uncarrier bullshit when you are worse than the other two carriers together. Your cheap misleading lease— MarceloClaure (@marceloclaure) July 2, 2015

He didn't stop there, though. "Your cheap misleading lease imitation is a joke," he wrote. "You trick people to believe that they have a 15 dollar iphone lease payment when it's not true. You tell them they can upgrade up to 3x but you don't tell them the price goes up to 27 dollars when they do. You say one thing but behave completely different. It's all a fake show. So its really #Tmobilelikehell."

Legere has not yet responded to Claure's tweets. But another Tuesday tweet accused Sprint of "reverting back to the old-school carrier way."

Legere has spoken publicly about how he wants to eclipse Sprint as the No. 3 U.S. carrier. But thus far, T-Mobile has not been successful. Sprint's aggressive tactics during the last quarter helped it remain the No. 3 U.S. wireless carrier, though efforts to retain and attract customers was costly and resulted in a revenue dip.

Sprint, meanwhile, is positioning "All-In" as a less complicated alternative to the early upgrade and no-contract plans offered by rivals like T-Mobile, which require phone down payments and offer varying monthly phone payments depending on when you expect to upgrade.

As a result, "All-In" bundles monthly service and phone lease charges into one bill, starting at $80. But as Re/code pointed out, that $80 does not include taxes and fees. It was that article that Legere tweeted, prompting the tweetstorm from Claure.